高岩温低湿环境下铁路隧道混凝土耐久性研究

Research on the Durability of Concrete under High Rock Temperature and Low Humidity Environment

依托在建铁路隧道工程,针对高岩温对隧道衬砌混凝土耐久性能的影响,通过试验室模拟现场高岩温、低湿度的施工环境,研究高岩温对纯水泥混凝土、单掺粉煤灰混凝土和双掺粉煤灰、矿粉混凝土耐久性能的影响规律,并从微观形貌方面分析高岩温对混凝土耐久性能的影响机理。结果表明:高温、低湿养护环境下,3种配合比的混凝土的耐久性能均随养护温度的升高而降低,抗氯离子渗透性能单掺粉煤灰混凝土最好,纯水泥混凝土最差;抗碳化性能基本相当;微观上分析单掺粉煤灰混凝土结构更密实、孔隙率更小。

This thesis aims to study the influence of high rock temperature on the durability of tunnel lining concrete with reference to ongoing railway tunnel project and to investigate the rules governing the influence of high rock temperature on the durability of straight cement concrete, the concrete mixed singly with fly ash and the concrete mixed with both fly ash and slag powder by simulating the engineering environment with high rock temperature and low humidity in laboratory. And it also analyses the mechanism of the influence of high rock temperature on the durability of concrete from a microscopic point of view. The results indicate that the durability of all three concretes tends to decrease with the increase of maintaining temperature; the concrete mixed only with fly ash is the best to resist chloride ions penetration while straight cement concrete is the worst; the carbonation resistance is almost the same for all the three; the structure of concrete mixed only with fly ash is more compact and the probability of porosity is much smaller as shown by the micro analysis.